Factor VIII is a protein found in blood plasma which acts as a cofactor in the cascade of reactions leading to blood coagulation. A deficiency in the amount of Factor VIII activity in the blood results in the clotting disorder known as hemophilia A, an inherited condition primarily affecting males. Hemophilia A is currently treated with therapeutic preparations of Factor VIII derived from human plasma or manufactured using recombinant DNA technology. Such preparations are administered either in response to a bleeding episode (on-demand therapy) or at frequent, regular intervals to prevent uncontrolled bleeding (prophylaxis).
Factor VIII is known to be relatively unstable in therapeutic preparations. In blood plasma, Factor VIII is usually complexed with another plasma protein, von Willebrand factor (vWF), which is present in plasma in a large molar excess to Factor VIII and is believed to protect Factor VIII from premature degradation. Another circulating plasma protein, albumin, may also play a role in stabilizing Factor VIII in vivo. Currently marketed Factor VIII preparations therefore primarily rely on the use of albumin and/or vWF to stabilize Factor VIII during the manufacturing process and during storage.
The albumin and vWF used in currently marketed Factor VIII preparations is derived from human blood plasma, however, and the use of such material has certain drawbacks. Because a large molar excess of albumin compared to Factor VIII is generally added in order to increase the stability of the Factor VIII in such preparations, it is difficult to characterize the Factor VIII protein itself in these preparations. The addition of human-derived albumin to Factor VIII is also perceived as being a disadvantage with respect to recombinantly-produced Factor VIII preparations. This is because recombinantly-derived Factor VIII preparations, in the absence of such added albumin, would otherwise contain no human-derived proteins, and the theoretical risk of transmitting a virus would be reduced.
Several attempts to formulate Factor VIII without albumin or vWF (or with relatively low levels of these excipients) have been described. For example, U.S. Pat. No. 5,565,427 (EP 508 194) to Freudenberg (assigned to Behringwerke) describes Factor VIII preparations which contain particular combinations of detergent and amino acids, specifically arginine and glycine, in addition to excipients such as sodium chloride and sucrose. The detergent, polysorbate 20 or polysorbate 80, is described as being present in amounts of between 0.001 to 0.5% (v/v), while arginine and glycine are present in amounts of between 0.01 to 1 mol/l. Sucrose is described as being present in amounts of between 0.1 and 10%. Example 2 of this patent asserts that solutions of (1) 0.75% sucrose, 0.4 M glycine, and 0.15M NaCl, and (2) 0.01 M sodium citrate, 0.08 M glycine, 0.016M lysine, 0.0025 M calcium chloride, and 0.4 M sodium chloride were not stable in solution over 16 hours, whereas solutions of (3) 1% sucrose, 0.14 M arginine, 0.1 M sodium chloride and (4) 1% sucrose, 0.4 M glycine, 0.14 M arginine, 0.1 M sodium ichloride, and 0.05% Tween 80 exhibited stability.
U.S. Pat. No. 5,763,401 (EP 818 204) to Nayer (assigned to Bayer) also describes a therapeutic Factor VIII formulation without albumin, comprising 15-60 mM sucrose, up to 50 mM NaCl, up to 5 mM calcium chloride, 65-400 mM glycine, and up to 50 mM histidine. The following specific formulations were identified as being stable: (1) 150 mM NaCl, 2.5 mM calcium chloride, and 165 mM mannitol; and (2) 1% sucrose, 30 mM sodium chloride, 2.5 mM calcium chloride, 20 mM histidine, and 290 mM glycine. A formulation containing higher amounts of sugar (10% maltose, 50 mM NaCl, 2.5 mM calcium chloride, and 5 mM histidine) was found to exhibit poor stability in the lyophilized state compared with formulation (2).
U.S. Pat. No. 5,733,873 (EP 627 924) to Osterberg (assigned to Pharmacia and Upjohn) discloses formulations which include between 0.01-1 mg/ml of a surfactant. This patent discloses formulations having the following ranges of excipients: polysorbate 20 or 80 in an amount of at least 0.01 mg/ml, preferably 0.02-1.0 mg/ml; at least 0.1 M NaCl; at least 0.5 mM calcium salt; and at least 1 mM histidine. More particularly, the following specific formulations are disclosed: (1) 14.7-50-65 mM histidine, 0.31-0.6 M NaCl, 4 mM calcium chloride, 0.001-0.02-0.025% polysorbate 80, with or without 0.1% PEG 4000 or 19.9 mM sucrose; and (2) 20 mg/ml mannitol, 2.67 mg/ml histidine, 18 mg/ml NaCl, 3.7 mM calcium chloride, and 0.23 mg/ml polysorbate 80.
Other attempts to use low or high concentrations of sodium chloride have also been described. U.S. Pat. No. 4,877,608 (EP 315 968) to Lee (assigned to Rhone-Poulenc Rorer) teaches formulations with relatively low concentrations of sodium chloride, namely formulations comprising 0.5 mM-15 mM NaCl, 5 mM calcium chloride, 0.2 mM-5 mM histidine, 0.01-10 mM lysine hydrochloride and up to 10% sugar. The xe2x80x9csugarxe2x80x9d can be up to 10% maltose, 10% sucrose, or 5% mannitol.
U.S. Pat. No. 5,605,884 (EP 0 314 095) to Lee (assigned to Rhone-Poulenc Rorer) teaches the use of formulations with relatively high concentrations of sodium chloride. These formulations include 0.35 M-1.2 M NaCl, 1.5-40 mM calcium chloride, 1 mM-50 mM histidine, and up to 10% of a xe2x80x9csugarxe2x80x9d such as mannitol, sucrose, or maltose. A formulation comprising 0.45 M NaCl, 2.3 mM calcium chloride, and 1.4 mM histidine is exemplified.
International Patent Application WO 96/22107 to Roser (assigned to Quadrant Holdings Cambridge Limited) describes formulations which include the sugar trehalose. These formulations comprise: (1) 0.1 M NaCl, 15 mM calcium chloride, 15 mM histidine, and 1.27 M (48%) trehalose; or (2) 0.011% calcium chloride, 0.12% histidine, 0.002% TRIS, 0.002% Tween 80, 0.004% PEG 3350, 7.5% trehalose; and either 0.13% or 1.03% NaCl.
Other therapeutic Factor VIII formulations of the prior art generally include albumin and/or vWF for the purpose of stabilizing Factor VIII and are therefore not relevant to the present invention. For example, U.S. Pat. No. 5,328,694 (EP 511 234) to Schwinn (assigned to Octapharma AG) describes a formulation which includes 100-650 mM disaccharide and 100 mM-1.0 M amino acid. Specifically, the following formulations are disclosed: (1) 0.9 M sucrose, 0.25 M glycine, 0.25 M lysine, and 3 mM calcium chloride; and (2) 0.7 M sucrose, 0.5 M glycine, and 5 mM calcium chloride.
While several attempts have been made to formulate Factor VIII without albumin or vWF, there remains a need for therapeutic Factor VIII formulations which are stable in the absence of albumin or other proteins.
The present invention relates to therapeutic Factor VIII compositions which are stable in the absence of albumin. In particular, the present invention comprises a Factor VIII composition comprising, in addition to Factor VIII: 4% to 10% of a bulking agent selected from the group consisting of mannitol, glycine and alanine; 1% to 4% of a stabilizing agent selected from the group consisting of sucrose, trehalose, raffinose, arginine; 1 mM to 5 mM calcium salt; 100 mM to 300 mM NaCl; and a buffering agent for maintaining a pH of approximately between 6 and 8. This composition can additionally comprise a surfactant such as polysorbate 20, polysorbate 80, PLUORONIC F68, or BRIJ 35. When the surfactant is polysorbate 80, it should be present in an amount of less than 0.1%.
The buffer of the Factor VIII compositions according to the present invention is preferably present in a concentration of from 10 mM to 50 mM, and is preferably selected from the group consisting of histidine, TRIS, BIS-Tris Propane, PIPES, MOPS, HEPES, MES and ACES. Advantageously, the buffering agent is either histidine or TRIS. The Factor VIII composition of the present invention can further comprise an antioxidant.
The Factor VIII compositions of the present invention include both a bulking agent and a stabilizer. The bulking agent can be present in an amount of from about 6% to about 8%, preferably about 8%. The stabilizing agent is preferably present in an amount of about 2%. Sodium chloride is also present in these compositions, preferably in an amount of from 150 to 350 mM, and more preferably in an amount of about 225 mM. The calcium salt of the composition is also preferably calcium chloride, and the composition itself is preferably in lyophilized form.
In another embodiment, the present invention can comprise a Factor VIII composition formulated without adding albumin which includes the following excipients in addition to Factor VIII: 2% to 6% hydroxyethyl starch; 1% to 4% of a stabilizing agent selected from the group consisting of sucrose, trehalose, raffinose, arginine; 1 mM to 5 mM calcium salt; 100 mM to 300 mM NaCl; and a buffering agent for maintaining a pH of approximately between 6 and 8. Preferably, such a composition comprises about 4% hydroxyethyl starch, and the NaCl is present in an amount of 200 mM. The stabilizing agent is also preferably present in an amount of about 2%.
In a further embodiment, the present invention includes a Factor VIII composition, formulated without albumin, comprising: 300 mM to 500 mM NaCl; 1% to 4% of a stabilizing agent selected from the group consisting of sucrose, trehalose, raffinose, arginine; 1 mM to 5 mM calcium salt; and a buffering agent for maintaining a pH of approximately between 6 and 8. Preferably, the NaCl is present in a concentration of about 400 mM.
In yet another embodiment, the present invention comprises a process for lyophilizing an aqueous Factor VIII composition in a container using a lyophilizer, wherein the process comprises an initial freezing step, and the initial freezing step further comprises the steps of: (a) lowering the temperature of the lyophilizer chamber to at least about xe2x88x9245xc2x0 C.; (b) raising the temperature of the chamber to between about xe2x88x9215xc2x0 C. and xe2x88x9225xc2x0 C.; and subsequently (c) lowering the temperature of the chamber to at least about xe2x88x9245xc2x0 C. In this process, the temperature of the chamber is preferably lowered or raised at a rate of between about 0.5xc2x0 C. and about 1.0xc2x0 C. per minute. In step (a), the temperature is preferably maintained for about 1 hour, and is lowered to about xe2x88x9255xc2x0 C. In step (b) the temperature is preferably maintained be xe2x88x9215xc2x0 C. and xe2x88x9225xc2x0 C. for between 1 and 3 hours, and more preferably is at xe2x88x9222xc2x0 C., and the temperature in step (c) is preferably maintained for about 1 hour. The Factor VIII composition used in this process preferably comprises between 4% and 10% of an agent selected from the group consisting of mannitol, glycine and alanine, and also preferably comprises between 1% and 4% of an agent selected from the group consisting of sucrose, trehalose, raffinose, and arginine. In addition, the Factor VIII composition used in this process also preferably comprises between 100 mM and 300 mM NaCl.
Definitions
As used herein, the terms below and variations thereof shall be defined as follows, unless otherwise indicated:
Factor VIIIxe2x80x94The Factor VIII molecule exists naturally and in therapeutic preparations as a heterogeneous distribution of polypeptides arising from a single gene product (see, e.g., Andersson et al., Proc. Natl. Acad. Sci. USA, 83, 2979-2983, May 1986). The term xe2x80x9cFactor VIIIxe2x80x9d as used herein refers to all such polypeptides, whether derived from blood plasma or produced through the use of recombinant DNA techniques. Commercially available examples of therapeutic preparations containing Factor VIII include those sold under the trade names of HEMOFIL M and RECOMBINATE (available from Baxter Healthcare Corporation, Deerfield, Ill., U.S.A.). Other preparations currently in development comprise primarily a single subpopulation of Factor VIII molecules which lack the B domain portion of the molecule.
International Unit, IUxe2x80x94International Unit, or IU, is a unit of measurement of the blood coagulation activity (potency) of Factor VIII as measured by a standard assay, such as one of the following:
One stage assay. One stage assays are known to the art, such as that described in Lee, Martin L, et al., An Effect of Predilution on Potency Assays of Factor VIII Concentrates, Thrombosis Research (Pergamon Press Ltd.) 30, 511-519 (1983).
Chromogenic assay. Chromogenic assays may be purchased commercially, such as the Coatest Factor VIII, available from Chromogenix AB, Molndal, Sweden.
Annealxe2x80x94The term anneal shall be used to indicate a step in the lyophilization process of a pharmaceutical preparation undergoing lyophilization, prior to the freeze-drying of the preparation, in which the temperature of the preparation is raised from a lower temperature to a higher temperature and then cooled again after a period of time.
Bulking Agentxe2x80x94For the purposes of this application, bulking agents are those chemical entities which provide structure to the xe2x80x9ccakexe2x80x9d or residual solid mass of a pharmaceutical preparation after it has been lyophilized and which protect it against collapse. A crystallizable bulking agent shall mean a bulking agent as described herein which can be crystallized during lyophilization, other than sodium chloride. HES is not included in this group of crystallizable bulking agents.
Freeze-drying, freezing, lyophilizingxe2x80x94xe2x80x9cFreeze-drying,xe2x80x9d unless otherwise indicated by the context in which it appears, shall be used to denote the portion of a lyophilization process in which the temperature of a pharmaceutical preparation is raised in order to drive water out of the preparation. The xe2x80x9cfreezingxe2x80x9d steps of a lyophilization process are those steps which occur prior to the freeze-drying stage. xe2x80x9cLyophilizing,xe2x80x9d unless otherwise indicated, shall refer to the entire process of lyophilization, including both the freezing steps and the freeze-drying steps.
Unless otherwise noted, percentage terms express weight/volume percentages and temperatures are in the Celsius scale.
Formulation Components
The Factor VIII compositions of the present invention include bulking agents, stabilizing agents, buffering agents, sodium chloride, calcium salts, and, advantageously, other excipients. These excipients have been chosen in order to maximize the stability of Factor VIII in lyophilized preparations. However, the Factor VIII compositions of the present invention exhibit stability in the liquid state as well.
The bulking agents used in the present formulations, which form the crystalline portion of the lyophilized product (except in the case of HES), are selected from the group consisting of mannitol, glycine, alanine, and hydroxyethyl starch (HES). Mannitol, glycine, or alanine are present in an amount of 4-10%, preferably 6-9%, and more preferably about 8%. When HES is used as a bulking agent, it is present in an amount of 2-6%, preferably 3-5%, and more preferably about 4%.
The stabilizing agents used in the formulations of the present invention are selected from the group consisting of sucrose, trehalose, raffinose, and arginine. These agents are present in the formulations of the present invention in an amount of between 1-4%, preferably 2-3%, more preferably about 2%. Sorbitol and glycerol were evaluated as possible stabilizers but were found to be poor stabilizers in the present formulations.
Sodium chloride is included in the present formulations in an amount of 100-300 mM, preferably 150-250 mM, and most preferably about 225 mM. In one embodiment of the present invention, odium chloride itself can be used without any of the aforementioned bulking agents, in which case it would be included in the formulation in an amount of between 300 mM and 500 mM NaCl, preferably 350 to 450 mM NaCl, and more preferably about 400 mM NaCl.
In addition, buffers are present in these formulations, because it is believed that the Factor VIII molecule can be adversely affected by pH shifts during lyophilization. The pH should preferably be maintained in the range of between 6 and 8 during lyophilization, and more preferably at a pH of about 7. The buffering agent can be any physiologically acceptable chemical entity or combination of chemical entities which have the capacity to act as buffers, including histidine, TRIS, BIS-Tris Propane, PIPES, MOPS, HEPES, MES and ACES. The full chemical designations of these buffering agents is listed in Table 1 below. Typically, the buffering agent is included in a concentration of 10-50 mM. When histidine is added to the formulations, concentrations of over 20 mM and preferably about 25 mM are used, alone or in combination with other buffers such as TRIS. Histidine is especially preferred for use in the compositions of the present invention, as described in greater detail below.
In order to preserve the activity of Factor VIII, it is important that the formulations of the present invention also include calcium or another divalent cation able to interact with Factor VIII and maintain its activity, presumably by maintaining the association of the heavy and light chains of Factor VIII. Between 1 mM and 5 mM of a calcium salt can be used, more preferably 3-4 mM, and most preferably about 4 mM. The calcium salt is preferably calcium chloride, but can also be other calcium salts such as calcium gluconate, calcium glubionate, or calcium gluceptate.
The Factor VIII compositions of the present invention also preferably include a surfactant, preferably in an amount of 0.1% or less, and more preferably in an amount of about 0.03%. The surfactant can, for example, be chosen from the group consisting of polysorbate 20, polysorbate 80, pluronic polyols, and BRIJ 35 (polyoxyethylene 23 lauryl ether). Several grades of pluronic polyols (sold under the trade name PLURONIC, manufactured by the BASF Wyandotte Corporation) are available. These polyols, of diversified molecular weight (from 1,000 to over 16,000) and physicochemical properties have been used as surfactants. PLURONIC F-38, of a molecular weight of 5,000 and PLURONIC F-68, molecular weight 9,000, both contain (by weight) 80 per cent hydrophilic polyoxyethylene groups and 20 percent hydrophobic polyoxypropylene groups. Tween-80, a commercial polysorbate, however, is preferred in the present formulations, in particular vegetable derived Tween-80.
The Factor VIII formulations of the present invention also preferably include an antioxidant. The addition of antioxidants to the lyophilized formulations of the invention has been found to improve the stability of these formulations, and thus extend their shelf lives. The antioxidants used must be compatible for use with a pharmaceutical preparation, and in addition are preferably water soluble. When adding antioxidants to a formulation, it is preferable to add such antioxidants as late in the process prior to lyophilization as possible, in order to avoid spontaneous oxidation of the antioxidant. Table 2 below lists suitable antioxidants, which are available commercially through companies such as Calbiochem and Sigma.
Of the foregoing antioxidants, glutathione is preferred. Concentrations in the range of about 0.05 mg/ml to more than 1.0 mg/ml have all been found to enhance the stability of Factor VIII compositions, and it is believed that higher concentrations would also be useful (up to the point of any toxic effects or adverse manufacturing effects, such as a depression of the glass transition temperature of the lyophilized product).
It has been found in particular that the combination of histidine and glutathione produces synergistically beneficial effects on the stability of Factor VIII compositions. Histidine, while acting as a buffer, can also act as a metal chelator. To the extent that Factor VIII inactivation is caused by metal-induced oxidation, histidine can therefore act to stabilize Factor VIII by binding such oxidizing metal ions. It is believed that by binding these metals, the glutathione (or indeed any other antioxidant present) is thereby able to provide further antioxidative protection, since the oxidative effect of the metal ions bound by the histidine has been contained.
Other chelating agents might also be used in the compositions of the present invention. Such agents should preferably bind metals such as copper and iron with greater affinity than calcium, if a calcium salt is being used in the composition. One such chelator is deferoxamine, a chelating agent that facilitates the removal of Al++ and iron. Deferoxamine Mesylate, C25H48N6O8*CH4O3S, can be obtained from Sigma (Sigma Prod. No. D9533). It is an aluminum and iron(II) chelator which chelates iron (as a 1:1 chelate complex) only in the +3 oxidation state, not +2 oxidation state, and can also bind manganese ion and other metals. Deferoxamine can be used advantageously in an amount of 0.25 mg/l.
The Factor VIII used in the present formulations can be either highly purified human plasma-derived Factor VIII or more preferably can be recombinantly produced Factor VIII. Recombinant Factor VIII can be produced by Chinese hamster ovary (CHO) cells transfected with a vector carrying a DNA sequence coding for the Factor VIII molecule. Methods for creating such transfected CHO cells are described, inter alia, in U.S. Pat. No. 4,757,006 to Toole, Jr., though alternative methods are also known to the art (see, e.g., U.S. Pat. No. 4,868,112, also to Toole, Jr., and PCT International Application WO-A-91/09122). The methods used to culture such CHO cells to produce Factor VIII are also known to the art, for example in European Patent Application No. 0 362 218 to Genetics Institute, entitled xe2x80x9cImproved method for producing Factor VIII:C-type proteins.xe2x80x9d Recombinant Factor VIII can, however, also be produced in other cell lines, such as baby hamster kidney (BHK) cells. The Factor VIII molecule itself, if recombinantly produced, can be either full-length Factor VIII or a deletion derivative thereof, such as a B domain-deleted Factor VIII molecule.
While the Factor VIII compositions described in this application can be lyophilized and reconstituted in the indicated concentrations, one of skill in the art will understand that these preparations can also be reconstituted in more dilute form. For example, a preparation according the present invention which is lyophilized and/or normally reconstituted in 2 ml of solution can also be reconstituted in a larger volume of diluent, such as 5 ml. This is particularly appropriate when the Factor VIII preparation is being injected into a patient immediately, since in this case the Factor VIII is less likely to lose activity, which may occur more rapidly in more dilute solutions of Factor VIII.
Formulation and Lyophilization Development
In order to achieve maximal stability, the Factor VIII compositions of the present invention are preferably lyophilized. During lyophilization, Factor VIII is converted from being in an aqueous phase to being in an amorphous solid phase, which is thought to protect the protein from chemical and/or conformational instability. The lyophilized preparation not only contains an amorphous phase, but also includes a component which crystallizes during lyophilization. This is thought to allow the rapid lyophilization of the Factor VIII composition and the formation of a more elegant cake (that is, a cake with minimal shrinkage from the sides of the container in which it was lyophilized). In the formulations of the present invention, the stabilizing agents have been selected to exist primarily in an amorphous phase of the lyophilized product, while the bulking agents (except HES) have been selected to crystallize during freezing.
Both the Factor VIII and the stabilizer are preferably dispersed in the amorphous phase of the lyophilized cake. The mass of the stabilizer is also preferably large compared to the other excipients in the amorphous form. In addition, the apparent glass transition temperature (Tgxe2x80x2) of the amorphous phase is preferably relatively high during freeze-drying, and the glass transition temperature (Tg) of the solid is likewise preferably high during storage. Crystallization of sodium chloride in the product was found to be desirable, since amorphous sodium chloride will depress the Tgxe2x80x2 of the amorphous phase.
In order to avoid the collapse of the cake of a particular composition, primary drying is preferably carried out at a product temperature below the apparent glass transition temperature of the freeze concentrate. An increase in drying time may also be required to offset a decrease in Tgxe2x80x2. Further information on lyophilization may be found in Carpenter, J. F. and Chang, B. S., Lyophilization of Protein Pharmaceuticals, Biotechnology and Biopharmaceutical Manufacturing, Processing and Preservation, K. E. Avis and V. L. Wu, eds. (Buffalo Grove, Ill.: Interpharm Press, Inc.), pp. 199-264 (1996).